The present invention relates to motor control centers, and more particularly to metal-enclosed control centers for housing high voltage contactor assemblies.
Motor control centers of the high voltage type, that is, adapted to receive voltages of 1000 volts and above are easily distinguished from lower-voltage motor control centers inasmuch as the large, heavy contactor assemblies required to make and break high voltage circuits are mounted in removable assembies, or carriages, which are racked into individual cubicles. The control apparatus for the contactors is ordinarily housed in a different cubicle, so that it may be repaired or maintained without necessitating access to the high-voltage apparatus.
For ease and economy in manufacturing, and for purposes of standardization, it has been found desirable to use standard size cubicles and mounting apparatus for contactors. At the same time, however, in some cases it has been found necessary to build enclosures of extra depth in order to accommodate oversized contactor carriages. Such contactor carriages are required in high current applications, when double fuses are required. With some contactor designs, the extra fuses are added in tandem in one end of the carriage, effectively adding to the length of the carriage and therefore requiring an extra-deep enclosure. In addition, for some two-high enclosures it has been conventional to run the bus work over the top of the uppermost cubicle so that an additional, overhead compartment must be provided which in turn extends the height of the cabinet above the conventional height. Accordingly, it will be understood that it would be highly advantageous to provide an improved construction for a two-high motor control center for accommodating an extra-deep contactor carriage assembly within the dimensions of an ordinary motor control center cabinet.
It is therefore an object of the present invention to provide a motor control center construction which makes improved use of space.
Another object is to provide a compact two-high motor control center for single and double-fused contactors.
Yet another object is to construct a motor control center of the high-voltage type which is more compact than those theretofore known.